Cold emailing can be productive. It works in a number of ways for sales, marketing, joint ventures, pr and more. Just don't expect it to close any deals immediately from it.

The critical points to improve your emails:
1. Who you are targeting - your ideal client (title, firm, revenue size, location, etc.) the more time you spend getting this right the better performance.
2. The volume - how many people are in your sweet spot.
3. The cadence - how often you keep contacting them. Don't expect 1 email to do much. 3-4 follow up emails is ideal.
4. The messaging - If it is all about you than you should look at writing emails about them and their needs first.

I have seen cold emails average 10% response rate - people saying yes, no or go to hell. Up to 40% for great messaging, spot on contacts and the right cadence.

As for "conversion" there are many factors that will impact you. If your product is brand new with no social proof than your responses will be much lower than an established firm.

Best of luck.